Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan.
In a medium bowl, whisk together 2 cups of flour, the sugar, baking powder, baking soda, and salt.
In a separate bowl, combine the melted butter, buttermilk, egg, and vanilla. Add the wet ingredients to the dry ingredients and mix until just combined.
Gently fold in the blueberries.
Pour the batter into the greased loaf pan and spread evenly.
In a separate bowl, combine the 1/2 cup of flour, brown sugar, and cold butter. Use a pastry blender to mix the ingredients together until it forms a crumbly topping.
Sprinkle the crumbly topping over the batter in the loaf pan.
Bake in preheated oven for 60-70 minutes, or until a toothpick inserted into the center comes out clean.
Remove from oven and let cool in pan for 10-15 minutes before transferring to a wire rack to cool completely.
Interesting Facts
Blueberry Loaf is a traditional American bread that is usually served for breakfast.
Blueberries are high in antioxidants and fiber, making them a healthy addition to any diet.
The crumbly topping is made from a combination of butter, sugar, and flour, which adds a sweet and crunchy texture to the loaf.